Okay. Let me clear a few things up to make this a more general answer.
What klm123 is talking about is the WoW token, a relatively new service. You can buy one for 20 units of your local currency (in the US and Europe, at least), which can be sold only through a Blizzard controlled exchange. The price is dictated by supply and demand and varies between regions. As of writing, the US price is hovering around 22k gold, whereas the EU one is roughly 40k, the Chinese token is 76k, and the Taiwan token is a whopping 230k. Buying a token from the exchange gives you a consumable version which cannot be relisted and will add one month of gametime to your account.
Okay. Still with me? Let's talk about making gold and how feasible it is to pay these prices.
While leveling through Warlords of Draenor content (90-100), you will earn approximately 15g per quest in direct gold rewards, and frequently you will receive a piece of equipment as well. This piece of equipment will be worth 20-50g in direct vendor value, but depending on your server it may be more profitable to disenchant and sell those materials on the auction house.
Previously, at maximum level WoW offered numerous 'daily' quests players could repeat for gold. The current expansion, Warlords of Draenor, has moved away from this model (there are significantly fewer dailies, with 1 apexis, 1 Harrison Jones, 1 trader, and 1 bounty per day). These are not the prime source of gold they once were, but can still contribute. Completing a Harrison Jones daily rewards 150g, the bount quest rewards 80g and a chance for a special quest, the Apexis daily rewards 800 apexis and 40g, and the trader takes materials of a specific type (depending on the day) and rewards you with primal spirits (50 spirits can be exchanged for a Savage Blood, which is worth about 200g depending on your realm).
Now, it's Garrison time. The Garrison provides several opportunities for making gold. You have followers, which you can send on missions that have follower rewards as well as player rewards. With level 100 followers, you can send them on missions which have base gold rewards of 100-500. There is a follower trait, Treasure Hunter, which increases the gold reward (and multiple traits on separate followers stack). With a good squad of Treasure Hunter followers, you can make several hundred gold per day without even lifting a finger. Follower traits are randomly rolled, so unless you get lucky with rolls you'll probably need to spend a lot of rerolls to get Treasure Hunter on your core followers. Thankfully, there's another solution: the Tavern. At level 3, the Tavern allows you to once per week select a trait or an ability to select for. Once you've chosen the trait or ability, you can select from 3 followers with that ability. This is the easiest way to find Treasure Hunter followers.
The Tavern also has another benefit: it offers daily quests. These daily quests reward between 15g and 60g each, as well as cosmetic items and http://www.wowhead.com/item=119037/supply-of-storied-rarities which has a chance to drop decent stuff. They're worth doing, but they require you queue for a dungeon and complete the objective as well as killing the dungeon's final boss. That brings me to dungeons. Your first random dungeon queue per day rewards (I believe) 100g and 50 Garrison resources. This can be increased by a call to arms buff which rewards you with http://www.wowhead.com/item=122607/savage-satchel-of-cooperation which contains extra gold and some augment runes (which can be resold). Dungeons typically take about 30 minutes (not counting queue time). In addition to dungeons, you can also queue for LFR (looking for raid, basically an easier version of current end-game raid instances). LFR will reward 154g per wing cleared, but only once per wing each week. LFR bosses will drop either an appropriate item of modest item level (highmaul LFR rewards 640, blackrock furnace rewards 655/660) or an augment rune (but each boss can only give you a reward once per week per difficulty). Augment runes can be sold on the auction house to other players. In addition, you can further increase the profitability of LFR/heroics by queueing with other people (basically, starting the queue when you have at least one other person in the party). Note that neither of these is likely to be the most efficient method of gathering gold, but they have other benefits.
Finally, crafting. Currently, crafting is focused around using a daily cooldown to produce materials that are bound to you which are then used to create items you can sell to other players. Since this is entirely player-driven it will vary wildly from realm to realm, but Enchanting and Jewelcrafting seem to be reliable moneymakers.
I almost forgot! So how viable is it to buy tokens and avoid the subscription fee? Well, it depends on your region and realm. I play on a North American realm and doing basically what I listed here on only one character I've been able to buy tokens easily. Doing garrison missions across several characters would probably be necessary for EU realms, maybe even some crafting cooldowns. I don't know how reasonable it is to pay with gold on Chinese or Taiwanese realms.